nrc-2009-0279-0038
TRANSCRIPT
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NUREG/CR-6112
BNL-NUREG-52394
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DISCLAIMER
This repor t w a s prepared as a n a c c o u n t
of work
s pons o red
by an agenc y of th e United Sta te s Government. Neither th e
United States Government nor any agency thereof, nor any
of thei r employees , ma ke an y warran ty , exp ress or implied ,
or assumes any legal l iabil i ty
or
responsibility for the
accuracy , comple teness , or usefu lness
of
any information,
appara tus , p roduct , o r proce ss disclosed , or represents th a t
its
us e would not infringe privately own ed r ights . Referen ce
herein to any speci f ic commercia l p roduct , p rocess , or
serv ice by t rade name, t rademark , manufac turer , or
o t h e r w i s e d o e s not necessarily constitute or imply
its
endorsement , recommendat ion , or favoring by the United
States
Government
or
any agency the reo f. The v iews and
opinions of authors expressed here in do
not
necessari ly
state or reflect t h o s e of th e United States Governmen t or
any agency the reo f .
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DISCLAIMER
Portions
of
this document m ay be illegible
in electronic image products. Images are
produced from th e best availabie original
document.
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Abstract
This report summarizes information required to estimate, at least qualiitively, the potential impacts of
reducing occupational dose limits below those given in 10CFR 20 (Revised).
For this study, a questionnaire was developed and widely distributed to the radiation protection commu-
nity. The resulting data together with data from existing surveys and sources were used to estimate the
impact of three dose-limit options; 10 mSv yr ' (1 remyr'),
20
mSv yrl
(2
rem yrl), and a combination of
an annual limit of
50
mSv yrl
(5
rem yf') coupledwith a cumulative limit, in rem, equal to age in years.
Due to the somewhat small number of responses and the lack of data
in
some specific areas, a working
committee of radiation protection experts from a variety of licensees was employed to ensure the
exposure data were representative.
The following overall conclusions were reached:
(1)
Although 10 mSv yf ' is a reasonable limit for many licensees, such a limit could be extraordinarily
difficult to achieve and potentially destructive to the continued operation of some licensees, such
as nuclear power, fuel fabrication, and medicine.
(2)
Twenty mSv yrl as a limit is possible for some of these groups, but for othersitwould prove
difficult.
(3)
Fifty mSv yrl and age in 1Os of mSv appear reasonable forall licensees, both in terms of the
lifetime risk of cancer and severe genetic effects to the most highly exposed workers, and the
practicality of operation. In some segments of the industry, this acceptability is based on the
adoption of a grandfather clause for those people exceeding or close to exceeding the cumula-
tive limit at this time.
Detailed nformation for fuel fabrication, waste management, manufacturing, well logging, and industrial
radiography s sparse and such data would be useful for a full understanding of the potential impact of any
reduction in the dose limits.
iii
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Contents
Page
Abstract ............................................................................... iii
Executive Summary
......................................................................
v
Foreword .............................................................................. xi
Acknowledgments
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
xii
1 Introduction ......................................................................... 1
2
Historical Background and Literature Survey
............................................... 2
2.1 1928to1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.2 1977to1987
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
2.3 1987to 1994
..................................................................
3
2.4
Background Summary
..........................................................
5
3
DataGathering
......................................................................
6
3.1 Existing Surveys ............................................................... 6
3.1.1
1992
Edison Electric Institute (EEI) Report on Dose Limits and Guidelines . . . . . . . . . . . . .
6
3.1.2 Departmentof Energy Report (DOE) on the Implications of the BElRV Report . . . . . . . . . . 6
3.1.3 Nuclear Regulatory Commission (NRC) Radiation Exposure Information and Reporting
System(RE1RS)
............................................................ 6
3.1.4
Environmental Protection Agency (EPA) Report on Occupational Exposure to Ionizing
Radiation in the United States ................................................. 7
3.2
Survey Performed for this Report
..................................................
7
3.2.1
Questionnaire Design
........................................................ 7
3.2.1.1
Options for Potential Dose Limits
........................................ 7
3.2.1.2
Impacts of Reduced Dose Limits
......................................... 7
3.2.1.3 1989
Dose Experience
................................................. 8
3.2.2 Questionnaire Distribution .................................................... 8
3.2.3
Working Committee on the Impact
of
Reduced Dose Limits
......................... 8
3.3 Comments Received to the Draft NUREG Report
....................................
8
4
SurveyResults
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
4.1
Edison Electric Institute (EEI) Report
............................................... 9
4.1.1
Administrative Control Levels
.................................................. 9
4.1.2 Annual Reported Doses for 1985and 1989 ...................................... 9
4.1.3
Cumulative Dose Administrative Guidelines
...................................... 9
4.1.4
Cumulative Reported Doses for
1989
..........................................
10
4.1.5
Projected Cumulative Doses for
1994 .......................................... 10
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Page
4.1.6
4.1.7
Effects of Changing the Annual Dose Guidance ..................................
10
Effects of Establishing a Cumulative Dose Limit
.................................. 11
4.2
Department of Energy (DOE) Report
............................................. 11
4.2.1
Costlmpact ...............................................................
11
4.2.2
4.2.3
4.2.4
Annual Reported Doses.
1978
to 1988 .........................................
12
Lifetime Cumulative Exposure Limits ...........................................
13
Impact on Facility Operations .................................................
13
4.3
Selected
1990
Data from NRC REIRS ............................................
14
4.4 Information Obtained from the 1984 EPA Report .................................... 18
4.4.1
4.4.2
4.4.3
Males ....................................................................
18
4.4.4 Females ................................................................. 19
Male and Female Workers in the Nuclear Industry
................................ 18
Correlation of Radiation Dose with Age
......................................... 18
4.5 Responses to the Request for Comment
..........................................
19
4.5.1 Nuclear Power Reactor and Nuclear Power Reactor Contractors ..................... 19
Organization of Licensees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19.5.1 I
4.5.1.2 Three Separate Responses were Received from Three of the Nuclear Power Plant
Sites
.............................................................. 21
4.5.2 Test and Measurement Including Industrial Radiography .......................... 22
Manufacturing and Distribution Including Cyclotron Produced Radiopharmaceuticals
.... 22
Fuel Fabrication. UF, Production
..............................................
22
Questionnaire Results Obtained in this Survey
............................................ 23
MedicaVDental and Veterinary Practice ............................................ 23
5.2
Nuclear Power Reactors .......................................................
25
Nuclear Power Reactor Contractors
.............................................. 29
Test and Measurements Including Industrial Radiography
.............................
31
Manufacturing and Distribution. Including Cyclotron Produced Radiopharmaceuticals ......
34
5.7 WasteManagement . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . 36
Fuel Fabrication. UF, Production
................................................. 37
5.9 Well Logging
.................................................................
39
Others (R&D. Regulatory) ......................................................
40
High Dose Groups Within an Industry
................................................... 41
4.5.3
4.5.4
5
5.1
5.3
5.4
5.5
Universities 33
5.6
5.8
5.10
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
6.1 Introduction
..................................................................
41
6.2
NRC-Sponsored Study on High Dose Group Workers
................................
41
6.2.1
Analysis of Dose Data Obtained in the Study .................................... 44
6.2.1.1
6.2.1.2
Pressurized Water Reactor Data ........................................
44
Boiling Water Reactor Data ............................................ 44
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Page
6.2.1.3
Contractor Data .....................................................
44
7 CostsAssociated With Dose Reduction Modificationsin the Nuclear Power industry .............. 46
7.1
Introduction ..................................................................
46
7.2
Costs (and the Related Dose Saved) of Selected Modifications Which Might be Employedto
ReduceExposure
.............................................................
46
7.3 Estimated Impacts ............................................................ 51
8
Summary ..........................................................................
55
8.1 Medical/DentalNeterinary
......................................................
55
8.1.1 1RemYf ................................................................
55
8.1.2
2RemYr ................................................................ 55
8.1.3
. . . . . . 55Rem Yrl and Cumulative Dose in Rem Less Than Age in Years Limit .......
8.2
Nuclear Power Reactor Plants and Their Contractors ................................
55
8.2.1 1
Rem PerYP
............................................................ 55
8.2.2 2
RemYf
................................................................
56
8.2.3 5
Rem Yf and Cumulative Dose in Rem Less Than Age in Years Limit
..............
56
8.3
Test and Measurement Including Industrial Radiography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
57
8.3.1 1
RemYr
................................................................ 57
8.3.2 2RemYr ................................................................ 57
8.3.3
5
Rem Yr and Cumulative Dose in Rem Less Than Age in Years Limit . . . . . . . . . . . . . . 57
8.4
Universitiesnot Including Medical. Dental. or Veterinary Schools
....................... 57
8.4.1 1
Rem Yr Limit
........................................................... 57
8.4.2 2
Rem Yf Limit ...........................................................
58
8.4.3 5 Rem Yf and Cumulative Dose in Rem Less Than Age in Years Limit . . . . . . . . . . . . . . 58
8.5 Manufacturing and Distribution Including Cyclotron-Produced Radiopharmaceuticals
......
58
8.5.1 1 Rem Yf Limit ........................................................... 58
8.5.2 2
Rem Yr Limit . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . .
58
8.5.3
5
Rem Yr and Cumulative Dose in Rem Less Than Age in Years Limit
.............. 58
8.6
Waste Management
........................................................... 58
8.6.1 1
Rem Yr Limit ...........................................................
58
8.6.2 2 Rem
Yf
Limit ...........................................................
58
8.6.3 5
Rem Yf and Cumulative Dose in Rem Less Than Age in Years Limit ..............
58
8.7
Fuel Fabrication. UF. Production
.................................................
58
8.8
Well Logging
................................................................. 59
8.9
Generai Conclusions ..........................................................
59
9
References .........................................................................
61
Appendix
A ............................................................................
64
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Figures
Page
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
7.1
7.2
4.1
4.2
4.3
4.4
4.5
4.6
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10
5.11
5.12
5.1 3
5.14
5.15
5.16
5.1 7
5.1 8
5.19
5.20
5.21
5.22
5.23
5.24
6.1
6.2
6.3
6.4
7.1
Annual Site Doses for Utility Personnel (UT) and Total Plant Workers(TO) ................... 9
Annual Site Doses for Utility Personnel (UT) and Total Plant Workers(TO) for 1985 and 1989 . . . 9
Cumulative Sie Doses for Utility and Contractor Personnel for 1989
.......................
10
Projected Cumulative Site Doses for 1994 Utility and Contractor Personnel
. . . . . . . . . . . . . . . . .
10
Average Annual Dose Equivalent for DOE Workers with Measurable Exposure. 1978-1988 . . . . 12
Number of
DOE
Employees
........................................................
12
Percent of Male Radiation Workers in Various Sectors .................................. 18
Percent of Female Radiation Workers in Various Sectors ................................ 18
Person-RemValues
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
52
Total Number of Reactors and Collective Dose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Tables
Annual Exposure Data 1990 ....................................................... 15
Annual Exposure Information for Industrial Radiographers* 1989
..........................
16
Annual Exposure Information for Fuel Fabricators* 1989................................. 16
Annual Exposure Information for Manufacturers and Distributors 1989
.....................
16
Summary of Annual Whole Body Distributions By Year and Reactor Type 1989
. . . . . . . . . . . . . .
17
Mean Annual Dose Equivalent for U.S. Radiation Worker ................................ 19
Impacts on MedicallDental and Veterinary Practice ..................................... 23
1989ExposureExperience......................................................... 24
Impacts in Nuclear Power Reactors
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25
1989ExposureExperience
.........................................................
26
1993 Exposure Experience (estimated)
..............................................
26
Impacts in Nuclear Power Reactor Contractors ........................................ 29
1989Exposure Experience
.........................................................
30
1993ExposureExperience......................................................... 30
Impacts n Test and Measurements Including Industrial Radiography....................... 31
1989ExposureExperience
.........................................................
32
Impacts in Universities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Impacts in Manufacturing and Distribution
.............................................
34
1993Exposure Experience
.........................................................
35
Impacts n Waste Management ... ... ... ... .. ...................................... 36
Impacts in Fuel Fabrication, UF, Production ........................................... 37
1989ExposureExperience......................................................... 38
1993 ExposureExperience......................................................... 32
1989ExposureExperience. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
1989Exposure Experience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
1989ExposureExperience
.........................................................
37
Impacts in Well Logging ........................................................... 39
1989ExposureExperience......................................................... 39
Impacts n Others (R&D, Regulatory)
.................................................
40
1989ExposureExperience
.........................................................
40
Whole-Body Dose Data for PWR Plants for 1988
.......................................
41
Whole-Body Dose Data for BWR Plants for 1988. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Whole-Body Dose Data for Various Worker Groups at PWR Plants for 1988
. . . . . . . . . . . . . . . .
43
Whole-Body Dose Data for Various Worker Groups at BWR Plants for 1988 . . . . . . . . . . . . . . . . 43
Estimated Costs and Dose Savings for Modifications at Nuclear Power Plants . . . . . . . . . . . . . . . 46
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Executive
Summary
The revised Nuclear Regulatory Commission (NRC) regulations 10 CFR
20
were based largely on the
1977 recommendations of the International Commission on Radiation Protection (ICRP), as interpreted
and promulgated by the Environmental Protection Agency (EPA) in 1987. Since then, the United Nations
Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the National Research Council
Committee on the Biological Effectsof Ionizing Radiation (BEIR), and the International Commission on
Radiological Protection (ICRP) have published new information indicating that the risk associated with
exposure to ionizing radiation
is
somewhat greater than that used by the ICRP and others in 1977. This
increase reflects additional cancers found in the Japanese survivors of the atomic bombings, new
dosimetry, and the adoption of a projection model which accounts for the excess cancer cases that are
expected to occur in those survivors who are still alive.
The ICRP recommended a dose limit of 100 mSv
in
5 years
(1
0 rem in five years) in its 1990
recommendations. The National Council on Radiation Protection and Measurements (NCRP)in 1987
recommended an annual limit of50mSv yr'
(5
rem yr') and suggested that no individual should exceed a
cumulative dose equal to hidher age in 1
Os
of mSv (age in rem). This suggestion has been raised to the
level of a recommendation in the 1993 Recommendations of the NCRP. Many countries in the world are
drafting new regulations adopting the ICRP system.
This study was requested by NRC to obtain a preliminary estimate of the potential impacts to NRC
licensees of any reduction in the dose limits. In general, the past indepth reviews of the impact of
lowering dose
limits
were based on an assumption that there would be no reductionin the source terms,
no improvement
in
equipment (remote tooling and surveillance), nor any increase in the productivity of
radiation workers.
Four approaches were used in this study. The first was the development and distribution of a question-
naire designed to solicit and evaluate information on the potential impacts of decreased dose limits from a
wide variety of licensees. The second approach was the review and analysis of previous surveys on dose
impacts and other data collections. These surveys were conducted by the Edison Electric Institute (EEI)
Health Physics Committee, the Department of Energy (DOE), Office of Health and Safety, and the Brook-
haven National Laboratory (BNL) ALARA Center. The data collections are those of the NRC Radiation
Exposure Information Reporting System (REIRS) and Environmental Protection Agency (EPA) 1984
Report on Occupational Exposure.
The third approach was to use a working committee to validate and extend the data obtained from the
questionnaire, and also review and comment on this report. This committee was composed
of
radiation
protection experts from various sectors of NRC licensees, together with individuals from Nuclear
Management and Resources Council (NUMARC), DOE, NRC, and the BNL ALARA Center. The fourth
approach was to incorporate the comments made to the draft NUREG/CR-6112.
Where possible, the data for 1989 was used as the basis for this report to allow meaningful intercom-
parisons. The BNL High Dose Group Study was based on 1988 data, and the EPA Report was based on
data of 1984 and earlier. Although the data for 1990 and 1993 suggests a reduction in individual and
collective dose has taken place, the overall conclusions drawn from the 1989 study remain valid.
Examplesof
costs
associated with reducing the source termin nuclear power plants were obtained from
the NUREGER-4373, Compendium of Cost-Effectiveness Evaluations of Modifications for dose
Reduction at Nuclear Power Plants, (Baum and Matthews, 1985).
From the information given in this report and that offered by the working committee, several tentative
conclusions can be drawn.
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The analysis suggests there would be minimal impact on collective doses, on costs of modifying facilities,
or on annual radiation-protection costs under the combined limit of50 mSv yr' (5 rem yr') and cumulative
dose in 1
Os
of mSv (rem) equal to age in years. The lifetime risk associated with thislimit - to an
individual maximally exposed -would be slightly less than that incurred by a similar individual controlled by
the ICRPs limit of 100 mSv in 5 years (10 rem in 5 years. However,
a
grandfather clause allowing up to
20 mSv yf'
(2
rem y f
)
after exceeding the age limit will be required for perhaps less than 1000 workers.
A 20
mSv yrl (2 rem yr') limit would appear achievable, although some tasks, particularly those in
medicine and in certain parts of the nuclear power industry, might prove extremely difficult o maintain.
Extensive modifications, such as steam generation, maintenance, and refueling including the installation
and use of robots and partialffullsystem decontamination, would be required for many tasks
in
nuclear
power plants. Depending upon the extent of the modifications, the collective dose might go up or down.
That is, extensive use of robots, source term reductions, and facility modifications might lower collective
doses. Less ambitious modifications, less decontamination, and the use of fewer robots might keep the
collective doses at about the same level while reducing individual doses; making no changes and allowing
the same tasks to be performed would necessarily result in higher collective doses. The working
committee suggested that with this annual limit, there could be a potential impact on safely since some
discretionary inspection and maintenance might be constrained.
For a 10 mSv yf' (1 rem yrl) limit, the risk to the most highly exposed individual would be lower than for
other options, i.e. equivalent to that of fatal accidents in United States industries, but the impacts are
expected to be quite serious for many of the industries which responded to the questionnaire. There are
tasks, again in medicine, which under present procedures could be prohibitively expensive. For industries
with large source terms, facility modifications and radiation protection costs would be extremely large (see
Section7). For these reasons, collective dose may increase substantially.
One additional issue must be kept in mind when assessing the impact of lower dose limits. That is, for
licensees to ensure that doses do not exceed the regulated dose limits, they routinely use administrative
limits. For example, with a regulatory limit of a50 mSv yr l
(5
rem yr'), an administrative limit of a
40
mSv
yr' (4 rem yr') might be used. At
20
mSv y f '
(2
rem yr-') limit, a 15 mSvyf' (1.5 rem yf') administrative
limit might be used, andso on.
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Foreword
On May 21,1991, the Nuclear Regulatory Commission (NRC) published a revision to 10 CFR Part
20,
Standards for Protection Against Radiation. The rule went into effect in June 1991, and all licensees
were required to implement the regulations on or before January 1,1994.
The revised 10 CFR Part 20 is based on the recommendations of the International Commission on
Radiological Protection (ICRP) in Publication
26
(ICRP 1977). In 1991, ICRP published revised recom-
mendations in Publication
60.
These recommendations were based upon revised dosimetry and
epidemiology, including the information presented in reports such as the 1988 United Nations Scientific
Committee on the Effects of Atomic Radiation (UNSCEAR). In this revision, ICRP reduced its recom-
mended dose limit to 100 mSv (1 0 rem) in
5
years, with the additional limitation that no more than50 mSv
(5
rem) is received in any one year.
In 1991, the National Council on Radiation Protection and Measurements (NCRP) recommended a lifetime
limit of 10 mSv
(1
rem) times age in years (NCRP 91). NCRP is currently reexamining
its
recommenda-
tions based on ICRP60.
As
a result of these recommendations, n 1988, the NRC staff initiated a study by Brookhaven National
Laboratory to analyze the potential impacts of reduced dose limits on its licensees and to provide a
technical base upon which to base future regulatory decisions. This NUREG summarizes the results of
that study, which included a survey of radiation protection experts. Even though the information presented
is not complete for certain categories
of
licensees due to unavailability, the conclusions for those where
data was available are considered valid.
Inview of the small number of licensees who responded to the survey, the NRC staff decided to publish a
draft of this report for public comment in the hopes that additional data and expert opinion would result,so
that a more extensive technical base could be developed. Licensees, agreement states, and all other
interested parties were encouraged to submit comments and relevant data on this draft report.
This NUREG incorporates the information from the comments received.
NUREGER-6112
is
not a substitute for NRC regulations, and compliance is not required. The a p
proaches and/or methods described in this NUREG/CR are provided for information only. Publication of
the report does not necessarily constitute NRC approval or agreement with the information cited therein.
YK
~ e G ~ ~ ~ - -
Radiation Protection
&
Health Effects Branch
Division of Regulatory Applications
Office of Nuclear Regulatory Research
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Acknowledg men&
This report is the result of efforts of many individuals. In addition to the author, the staff of the Brookhaven
National Laboratory (BNL)
A U R A
Center, John Baum, Tasneem Khan, Bruce Dionne, and Casper Sun
made major contributions to the report.
The working committee of Larry Brennecke, Thomas McLeod, Thomas Gaines, George OBannion,
Howard Elson, Frank Rescek, Frank Roddy, Robert Robinson, Alan Roecklein, Anthony Weadock, George
Powers, Ralph Andersen, Jay Maisler, Tasneem Khan, and Bruce Dionne provided data, insightful com-
ments and suggestions, and helpful editorial suggestions.
Alan Roecklein and the Project Manager, George Powers, gave us the necessary oversight, advice, and
support required to complete this phase of the work.
Finally, the patience and precision of Karen Wagner in preparing and editing the report is gratefully
acknowledged.
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Impact
of
Reduced Dose Limits
on NRC Licensed Activities
1 Introduction
The revised Nuclear Regulatory Commission (NRC)
regulations, 10 CFR
20,
(NRC, 1991) impose an an-
nual effective dose equivalent limit of
50
mSv
(5
rem)
on occupationally exposed workers. This requirement
corresponds to that given in the Environmental Pro-
tection Agency's (EPA's) 1987 Radiation Protection
Guidance for Occupational Exposure-Recommen-
dations (EPA, 1987) approved by the President. Both
of these agencies based their requirements largely on
the 1977 recommendations of the International
Commission on Radiological Protection (ICRP) given
in their Publication 26 (ICRP, 1977).
In
the
late 1980s, the Radiation Effects Research
Foundation (RERF) updated the data on their life-
span study of the Japanese atomic bomb survivors to
account for the increase in cancer incidence as a
function of dose associated with a revision in the
dosimetry (Shimizu et al., 1987; 1988). Another in-
crease in the risk factors resulted from a potential
increase in the risk associated
with
further epidemio-
logical support for the multiplicative or relative risk
projection model. The National Council on Radiation
Protection and Measurements (NCRP) modified their
basic recommendations to reflect this preliminary data
in 1987 (NCRP, 1987). The NCRP also noted the
substantial decrease
in
the frequency of fatal indus-
trial accidents that had been the basis for the risk-
based dose limit given by ICRP
in
1977. This fre-
quency decreased from about 1
x
1
4
yf ' in the early
1970s to about
4
x 10'5 n the mid 1980s.
Shortly thereafter, the United Nations Scientific Com-
mittee on the Effects
of
Atomic Radiation (UNSCEAR)
and the National Research Council Committee on the
Biological Effects of Ionizing Radiation (BEIR) pro-
duced the 1988 UNSCEAR Report (UNSCEAR, 1988)
and the 1990 BEIRV Report, (NASBEIR, 1990) re-
spectively.
1
4
rem-') for adults, and about
5 x
1
O-2Sv'
5
x
10-4
rem ) for the total population (ICRP, 1991). Although
the ICRP has changed
its
criteria for selecting dose
limits, this increased estimate of the risk of fatal can-
cer alone from 1.25
to 4 x
1
0-' Sv'
1.25
to
4
x 1
O4
rem-') given in ICRP Publication 26 (ICRP, 1977)
suggested that an annual limit of50 mSv
(5.0
rem)
over a working lifetime was unlikely to be considered
acceptable. Their solution, given in Pubiication60,
was to recommend an occupational limit of 100 mSv
in 5 years (20 mSv yrl )
[I
em in 5 years (2 rem yr')]
with
an additional limit of50mSv (5 rem) in any year.
The International Atomic Energy Agency
(IAEA)
and
the Commission of European Communities (CEC)
already have begun to revise their basic safety stan-
dards to conform with ICRP's new recommendations.
In light of these developments, in 1988 the NRC re-
quested that a preliminary study be madeto analyze
the potential impacts of reduced dose limits on its
licensees, and to provide a technical base for making
future regulatory decisions on limits. This report sum-
marizes the results of a review on the impact of re-
duced dose limits o NRC licensees.
Using the preliminary information from the 1988
UNSCEAR report, the ICRP began a major revision to
its
recommendations, beginning
with
a detailed review
of the data. The revised estimate of the lifetime fatal
cancer risk for low dose or low dose-rate exposure
given in ICRP Publication 60is -4 x 10-' Sv' (-
4
x
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2.1 1928 to 1977
The first widely accepted dose-limiting recommen-
dations were based on keeping exposures below the
threshold for observable effects (Mutscheller, 1925).
By the end of the second world war, theselimits,
which by then reflected concern over leukemia and
genetic effects, were expressed as
300
mremheek to
tissues at a depth of
5
cm
or
more in the body, and
600
mreml week to the surface of the body (NBS,
1954; ICRP, 1954). These values were equivalent to
the later limits of 15 rem yr' to most of the individual
organs with the exception of the blood-formingtis-
sues, the gonads, and the lens of the eye (NCRP,
1971; ICRP, 1959a), and 30 rem yr' to the skin (NRC,
1960; ICRP, 1964).
After the second world war, there was much public
concern over world-wide fallout from nuclear tests
(Divine, 1978). Mueller and others were convinced
that for genetic effects at least, there was a linear no-
threshold response (Mueller, 1927; Lea, 1947). The
National Academy of Sciences-National Research
Council (NAS-NRC, 1956) and the Briish Medical
Research Council (MRC, UK, 1956) formed expert
committees to examine the radiobiological evidence.
The basic consideration was the need to restrict the
genetic damage to both exposed individuals and to
the general population. Based heavily on the dose-
effect relationship for genetic effects seen in Drosoph-
-
la and on the observed genetic burden seen in hu-
mans, assumed to be partly due to the natural radia-
tion background (Haldane, 1948), the next set of limits
reflected:
1)
a need to limit cumulative dose, and 2) a
need to restrict the cumulative dose to workers in their
reproductive years below that for older workers. The
resulting limits for whole-body penetrating radiation
were (age
-
18) 5 rem cumulative dose and3 rem/
quarter (NCRP, 1957; ICRP, 1959b).
By the early 60s, the data from the Japanese survi-
vors of the atomic bombs began to emerge (UNS-
CEAR, 1962). This data, together with that from the
early radiologists and British spondylitic patients,
suggested that the incidence of leukemia increased
as a result of radiation.
A decade later,
it
was apparent that the incidence of
certain solid tumors also increased in the Japanese
survivors, the British spondylitic patients, and women
with mastitis who had been treated
with
X rays
(UNSCEAR, 1972; BEIR, 1972).
Consequently, he InternationalCommission on
Radiological Protection (ICRP), the National Council
on Radiation Protection and Measurements (NCRP),
and the Federal Radiation Council (FRC) all re-
emphasized the need to keep exposure as low as
practical, practicable, or reasonably achievable.
2.2 1977
to
1987
In the middle 70s, the United Nations Scientific Com-
mittee on the Effects of Atomic Radiation (UNSCEAR,
1977) felt there was sufficient nformation rom the
Japanese atomic bomb survivors to estimate the risks
to individual organs. This led to the adoption by the
ICRP in 1977 of the effective dose equivalent con-
cept', with
its
attendant w values (weighting factors
representing he proportion of the stochastic risk from
individual issues relative to the risk to the whole body
when the body is irradiated uniformly). In addition, the
ICRP justified the 50mSv yfl (5 rem yr') limit on the
basis that the average dose would be less than 10
mSv yr'(1 rem yrl) and, as UNSCEAR had done, as-
sumed that the risk from low dose, low dose-rate
exposure was
2.5
times less than that seen in Japa-
nese atomic bomb survivors. The first of these two
criteria led ICRP in 1977 to eliminate the (age
-
18)
5
rem recommendation.
Perhaps the greatest significance of the 1977 ICRP
Publication 26 was the development of the close rela-
tionship between risk and dose limits. Simply put, an
average excess risk of fatal cancer and severe ge-
netic effects of
l
I O - *
Sv'
(1x
l 4
rem-') was judged
to be acceptable by the ICRP.
At the time that ICRP published their recommended
occupational limito f 50 mSv yrl (5 rem yf ) (ICRP,
1977), several different sets of limits were being
recommended or used in the United States.
'
The concept originated in ICRP Publication 26 (ICRP, 1977)
although the term effectivedose equivalent was not intro-
duced until 1978 (statement from the 1978 StockholmMeeting
of the ICRP Annals of the ICRP,
Vol.
2, No.
1.
(1978).
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The NCRPwas recommending a limit of
5
rem yf'
and (age - 18)5 rem (NCRP, 1987); the Federal Radi-
ation Council (FRC) was recommending rem/quarter
and (age-18)
5
rem (FRC, 1960); both the Nuclear
Regulatory Commission (NRC) and the Occupational
Safety and Health Administration (OSHA) were en-
forcing 3 remlquarter and (age-18) 5 rem, and the
Department of Energy (DOE) were enforcing rem/
quarter and5 rem yr'. During this period, the Natural
Resources Defense Council (NRDC) petitioned both
the EPA and the NRC to lower occupational exposure
limits in the United States. The federal agencies'
response to the petition eventually led to several re-
ports on the impact of lowering the Annual Dose
Equivalent limit from
5
rem to
0.5
rem.
The earliest report was prepared or Stone and Web-
ster Engineering Corporation by Warman et al., 1978.
Their basic conclusion was that a decrease in the
dose limit to about2 em yrl would exponentially
increase both collective dose and the number of addi-
tional workers needed. Below2 em yrl, the increase
per unit dose reduction would be even greater. These
results were based on the dose distribution of Pres
surized Water Reactor (PWR) and Boiling Water Re-
actor (BWR) workers in 1976. The basic assumptions
were that the dose received by workers that was
above any new dose limit would have to be received
by additional workers, and that the dose rates existing
at the power plants at that time would be represen-
tative of future dose rates. All workers were assumed
to be productive 90% of the time.
A more detailed analysis was made by the Atomic
Industrial Forum (AIF) a few years later in which the
impacts were analyzed by tasks (AIF, 1978). The
overall conclusion, taken from a statement in the
report, was While exposure and costs do increase,
manpoweris considered the most significant con-
cem. Again, it is important to recognize that AIF
assumed
(1)
that there
will
be no significant design
improvements made leading to the reduction of expo-
sure or to improved operation or maintenance , and
(2) that work in a radiation environment at commer-
cial nuclear power plants
will
not be performed signifi-
cantly differently at lowered exposure limits than it is
at present limits.
The DOE conducted a similar study for their facilities
(DOE, 1979). Rather than employ the models used in
the AIF study, DOE relied on a detailed questionnaire
and a review committee. However, their conclusions
3
Historical Background
were no different than those
of
the two reportsde
cussed above, except that the impacts occurred at
slightly lower doses because DOE was then using a
5
rem yrl limit. The DOE report recommended that the
concept of As Low As Reasonably Achievable
(ALARA) should have greater attention than a reduc-
tion in dose limit. Also, there was more emphasis on
potential facility modifications and reduction of source
terms.
Fortunately, since these reports were issued, extraor-
dinary strides in reducing exposure using the
ALARA
principle and restrictive administrative imits have
significantly reduced collective dose without increas-
ing the average annual dose to workers. In fact, the
combination of improvements in productivity, design,
and source-term reduction has decreased the average
individual dose at both NRC licensees and DOE facili-
ties over the past decade. This was most clearly
demonstrated in the Naval Nuclear Propulsion Pro-
gram (Schmitt and Brice, 1984), and in the commer-
cial nuclear power industry (Brooks, 1988).
2.3 1987 to 1994
Today, the weight of new radiobiologicalevidence on
dose limits is as important as it was in the early
1950s. The incorporation of (age
-1
8)
5
rem into the
recommendations and limits at that time was ac-
cepted with l i l e difficulty (except, perhaps, in uranium
mining and fuel fabrication). The most recent evi-
dence from the Japanese
survivors,
reviewed by
UNSCEAR (UNSCEAR, 1988) and the National Aca-
demy of Sciences (NAS) Committee on the Biological
Effects of Ionizing Radiation (BEIR, 1990), suggests
that the risks of fatal cancer and severe genetic ef-
fects may be up to
4
times greater than those esti-
mated in 1977.
Reacting to the emerging information from the Rad-
ation Effects Research Foundation (RERF) in Japan
(Preston and Pierce, 1981), the ICRP .ssued a state-
ment in 1987 following
its
meeting in Como, Italy
(ICRP, 1987). The Commission suggested that:
(1)
revised dosimetry could increase the cancer
risklunit dose by a factor of 1.4, (2) the observed
increase in the incidence of solid tumors in younger
members of the exposed population might lead to a
combined increase of a factor of2, and (3) the rela-
tive risk projection model could increase the risk factor
even further. The Commission also noted that a new
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Historical Background
set of basic recommendationswould beavailable in
1990.
Mostworkers seem to have been adequately pro-
tected under the (age
-
18)
5
rem dose limit. The
average annual exposure to monitored workers with
measurable exposure was about 230 mrem (EPA,
1984). Using the 1990 ICRP risk estimates of 5
X 1
-*
SV'
-4
x
1
O4
rem-') for fatal cancer for those aged
18-65, the lifetime of fatal cancer risk to an individual
receiving he annual exposure of 2.3 mSv (230 mrem)
is predicted to be
-1
x
1
4. This figure is comparable
to the risk of accidental death in U.S. industry.
However, for a worker receiving 50 mSv
(5
rem) in
one year, these same risk estimates project a lifetime
risk of attributable fatal cancer and severe genetic
effects
at
2.5
x
1
03.
Such an annual level of risk is
compar-able to that associated with the upper range
of risk in mining, construction, and agriculture, includ-
ing deep-sea fishing. For those few workers who may
receive annual doses near the dose limit over much of
their working lives, the cumulative level of risk may be
unacceptable.
Consequently, the National Radiation Protection
Board (NRPB)
in
England ssued interim guidance in
November 1987 (NRPB, 1987) in which they recom-
mended that
...
occupational workers exposure
should be
so
controlled as not to exceed an average
effective dose equivalent of 15 mSv yr'.*'
This NRPB Guidance is, in fact, quite similar to the
1987 recommendation of the NCRP in
its
Report 91
(NCRP, 1987)
in
which the Council stated ...the com-
munity of radiation users is encouraged to control their
operations in the workplace in such a manner as to
ensure, in effect, that the numerical valueof the indi-
vidual worker's lifetime effective dose equivalent n
tens
of
mSv (rem) does not exceed the value of his or
her age in years. Both approaches would lead to
lifetime doses below 750 mSv (75 rem).
Both guidances reflected an expectation that risk
estimates would increase and safe industries would
continue to become safer.
In general agreement with other countries, the Federal
Republic of Germany stated that before changing
annual dose limits
it
will await completion of interna-
tional discussion following the issuance of the 1990
ICRP recommendations. However, the German au-
thorities made a rather dramatic change in their rec-
ommendations (Kaul et al., 1989):
Under the present conditions, the German
Commission on Radiological Protection
(SSK)
recommends hat the rule of minimization be
applied more strictly and that in the future, in
adherence to the annual dose limit of the
Radiological Protection Ordinance of
50
mSv,
a total dose of400 mSv during a whole work-
ing lifetime shall not be exceeded (occupa-
tional lifetime dose).
A
comprehensive report on the impacts of dose-limit
reduction was produced n 1988 for the Electrical
Power Research Institute (EPRI) (Le Surf, 1988). The
author suggested that although there have been sig-
nificant reductions n both individual and collective
doses in the U.S. nuclear power industry, basic and
fundamental changes are needed
if
this industry is to
comply with lower limits. He points out that other
countries have successfully reduced exposure in
three ways: first, by changing the philosophy of radia-
tion protection, emphasizing line responsibility and
training; second, by introducing aggressive measures
to reduce the source term; and third, by incorporating
similar approaches to prevent the buildup of radiation
fields. The NRC established an AIARA Center at
Brookhaven National Laboratory (BNL), which main-
tains a database for these issues (Khan et at., 1992;
Baum and Khan, 1992; Khan et al., 1991b).
In January 1991, the ICRP issuedits Publication 60,
The 1990 Recommendations of the International
Commission on Radiological Protection (ICRP, 1991)
recommending a limit
of
100 mSv in
5
years, with the
caveat that no more than
50
mSv be allowed in any
one year. The Commission's intention was to limit the
lifetime effective dose to
-
1 Sv
(100
rem) and the
average annual effective dose equivalent to 20 mSv
(2 rem).
The most recent NCRP recommendationsgiven in its
Report 116, Limitation of Exposure o Ionizing Radia-
tion, raise the guidance given in NCRP Report 91
,
Recommendation on Limits for Exposure to Ionizing
Radiation, on a lifetime dose in 1
Os
of mSv equal to
age in years (lifetime dose in rem equal to age in
years) to the level of a recommendation. The NCRP
Report 116 also maintains the recommendation of
50
mSv yr'
(5
rem yr').
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Historical Background
It
is importand o know that UNSCEAR reaffirmed he
ICRP risk estimate in both their 1993 (UNSCEAR,
1993) and 1994 (UNSCEAR, 1994) reports.
The
MEA
has revised of the Basic Safety Standards
as has the CEC. The European Community
is
ex-
pected to have a new set of requirements based on
ICRP
60
in place by the middle of this decade, with
many other nations following soon after.
2.4 Background
Summary
In general, past in-depth reviews of the impact of
lowering dose limits were based on an assumption
that there would
be
no reduction in the source terms,
no improvementinequipment (remote tooling and
surveillance), nor any increase in the productivityof
radiation workers. However, reductions n dose limits
led to the realization hat all of these assumptions
may be incorrect.
It
is essential that any review of the
impact of lowering dose limits addresses the financial
impact of lowering collective doses, not simply the
redistribution of existing exposure.
5
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3 Data Gathering
In
this study we proposed to use existing surveys and
to obtain opinions on the impacts of reductions in the
dose limit from as broad a spectrum of users as possi-
ble without resorting to an intensive site-by-site as-
sessment.
In
addition to reviewing such surveys,
such as the EEI, the DOE, and recent NRC-spon-
sored studies on dose reduction, therewas a wide-
spread distribution of a questionnaire to elicit the
responders' opinion and to obtain specific data to
assist in our overall assessment of the impact. Data
from the NRC's Radiation Exposure Information and
Reporting Sysfem (REIRS) and the 1984 EPA Report
on Occupational Exposure were used to validate the
survey data. In addition, data and information su p
plied in the comments received on the draft
NUREGER-6112
will
be reviewed.
3.1
Existing
Surveys
3.1 I 1992 Edison Electric Institute (EEI)
Report on Dose Limits and Guide-
lines
Questionnaires were sent to all members of the
EEI
Health Physics Committee addressing the following
topics:
1)
current practices and experience on ad-
ministrative dose-control levels, 2) cumulative dose
guidelines and experience,3) projected mpacts asso-
ciated with lifetime dose limits, and 4) effects of a
reduced annual dose limit and of establishing a cumu-
lative dose limit. Twenty-seven individuals replied,
representing 23 nuclear utilities. These responses
covered 43 Pressurized Water Reactors, 18 Boiling
Water Reactors, and a High Temperature Gas Cooled
Reactor, encompassing more than half the nuclear
power plants (62 out of 108 units in 1989). They
obtained dose data for> 14,500 and> 12,500 individ-
uals with doses
> 500
mrem in 1985 and 1989,
respectively. For these two years, the number of
personnel at U.
S.
ower reactors with doses
> 500
mrem was about 27,000 and 25,000, respectively.
The responses were stored in a computer database
and published as graphs and tables, with the authors
of the report using their best udgment to interpret the
utilities' responses. The full survey is reported n the
EEI Nuclear Report, Utility Response to Question-
naire on Dose Limits (EEI, 1991); Section 4.1 gives a
brief summary.
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6
3.1.2
Department of Energy Report
(DOE) on the Implications of the
BElRV Report
In response to a request by the Secretary of Energy,
the Office of Health reviewed the implications of the
BElRV report for the Department of Energy (DOE).
A
questionnaire was developed by a DOE internalRe-
view Committee to survey DOE contractors to esti-
mate costs for additional personnel, programmaticup-
grades, and engineering modifications that would
be
needed to comply
with
an anticipated reduction n the
dose limits.
The questionnaire was sent to the Albuquerque, Chi-
cago, Idaho, Nevada, Oak Ridge, Richland, San Fran-
cisco, and Savannah River Field Offices on January
30, 1990, for distribution to their contractors. Thirty-
seven contractor sites responded, which operate the
following types of nuclear facilities: accelerators,
fuelhranium enrichment, fuel fabrication, fuel
processing, maintenance and support, hot cells, reac-
tors (test, research, and production types), research
and development, fusion, waste processing/storage,
weapons fabrication and testing, tritium production,
and radiography. Two significant contributors to
DOES collective dose, the Rocky Flats plant in
Golden, Colorado, and
Los
Alamos National Labo-
ratory in
Los
Alamos, New Mexico did not respond.
The scope and findings of the survey are given
in
the
Final Report to the Secretary of Energy; Implication
of the BElR
V
Report to the Department of Energy
(DOE,
1990). The results are summarized in Section
4.2 of this report.
3.1.3 Nuclear Regulatory Commission
(NRC)
Radiation Exposure Infor-
mation and Reporting System
(REIRS)
The NRC established a radiation exposure informa-
tion and reporting system (REIRS) and publishes data
from
six
of the seven categories of NRC licensees
subject to the reporting requirementsof 10 CFR
20.407. Selected data from NUREG 0713
Vol
12
(Raddatz and Hagemeyer, 1993), which presents data
for 1990, are given in Section 4.3 of this report; it
serves as one elementof the processof ensuring that
the survey responses provide a realistic picture of the
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exposure statistics. Itshould be noted that the REIRS
data contains information from NRC licensees only.
Companies that are licensed by agreement states do
not report their exposures to the NRC, so the data for
industrial radiography, manufacturing, and distribution
of specified quantities of by-products and low-level
waste do not reflect the total United States exposure.
3.1.4 Environmental Protection Agency
(EPA) Report on Occupational Ex-
posure to Ionizing Radiation in the
United States
Because the U.
S.
nuclear industry is spread over
many diverse sectors,
it
is very difficult to get a com-
plete, comprehensive picture of the radiation expo-
sure of all radiation workers. Fortunately, the Environ-
mental Protection Agency (EPA) made a study which
covers almost every sector (EPA, 1984). We ana-
lyzed their data to gain detailed information for one
year over the entire U.
S.
nuclear industry. Although
the study is several years old, it is by far the most
detailed of its kind and its main conclusions are useful
to the current effort. Section 4 presents our analysis.
3.2 Survey Performed for this
Report
A questionnaire designed to elicit response from
a
wide variety of radiation users was developed
(Appendbc A).
A working group of technical experts (see
3.2.3)
e-
viewed the data from the questionnaire and obtained
additional data where needed.
3.2.1 Questionnaire Design
Three classes of information were judged to be impor-
tant: The responders' estimate of
the
impact as a
function of several dose limiting options; their organ-
ization's preliminary data on exposures; and lastly,
their comments and suggestions. The questionnaire
also solicited information about the respondent's
organization and asked if the respondee could be-
come a member of a working group to review and
assess the results of the questionnaire.
7
Data Gathering
3.2.1 I
Options
for
Potential
Dose
Limits
Four dose-limit options were proposed, each reflect-
ing a rational response to the new risk estimates. The
first
option considered was 2 rem yf', which was the
basic recommendation in the widely circulated drafl of
the ICRP revision to its Publication 26 (the final rec-
ommendation was
100
mSv in five years, and less
than
50
mSv in any one year).
The second option was
1
rem yfl, based on the
UNSCEAR 1988 risk estimate being about 4 times the
UNSCEAR 1977 risk estimate. Therefore,
it
might be
prudent to reduce the
5
rem yr ' limit to about
1
rem
yrl to account for this difference. In addition, the age-
related approach suggested in NCRP91 could result
in 1 rem yf ' if
the
regulatory agency is concerned
about the record-keeping of cumulative dose limits.
Furthermore, perhaps this isthe lowest level that
could be imposed and
still
permit widespread use of
radiation and radioactive materials.
The third
option
was age in rem and
5
rem yf', which
simply escalates the guidance given in NCRP Re-
port 91 to a regulatory limit. Itallows up to 5 rem yf'
which permits the continued operation of previously
designed facilities without significant modifications,
but ensures that the lifetime risk to any individual
will
be less than 100 rem.
Fourth, a limit of age in rem and2 rem yrl was given
because a regulatory agency may wantto regulatethe
rate of exposure more closely than option3. In addi-
tion, this limit option appears
to
be closer
to
the
ICRPs recommended limit of
100
mSv in five years,
and has the advantage of restricting exposure in the
early years of working life more than does option
3.
These four options are not intended as suggestions
for new regulatory limits, but merely as the most prob-
able ones which a regulator might consider.
3.2.1.2
Impacts
of
Reduced
DoseLimits
Previous studies on the impacts of reduced dose
limits usually cite increased costs and increased col-
lective dose. The questionnaire asked that costs be
broken down between those required for modifying
the facility, and operating costs. The first are
expected to
be
one-time costs, and the latter recurring
costs.
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Data Gathering
3.2.1.3
1989 Dose Experience
To allow BNL to make a less subjective assessment,
six
items of related data were requested. The first
three were the number of employees
with
exposure in
excess of
5
rem,
2
rem, and
1
rem in 1989, data
clearly related to the potential limits given in the
o p
tions. The fourth item was a request for information
on the number of employees whose current lifetime
dose in rem exceeds their age, which would highlight
any need for grandfathering . The number of
employees with measurable dose was requested to
judge the weight that should be given to the specific
data in the questionnaire. The annual collective dose
also was requested, which, when taken with the
above data, could provide information on the dose
distribution, and assist in evaluating the answets
about the impact on collective dose.
3.2.2 Questionnaire Distribution
The questionnaire and an explanation ofits intended
use was published in the July 1990 issue of the
Health Physics Society Newsletter, which is distrib-
uted to the nearly 6,000 members of the society. The
societyis composed of scientists, engineers, and
professionals concerned with radiation protection
throughout the United States,so
it
was felt that virtu-
ally all categories of radiation users would have ac-
cess to
it.
A letter describing the questionnaire andits
availability was published in the newsletter of the
American Association of Physicists in Medicine. The
majorityof Medical physicists and medical health
physicists belong to this society,
so
this category of
radiation users was given a unique opportunity to
participate.
3.2.3 Working Committee on the Impact
of Reduced Dose Limits
From the inception of this study, we recognized that
the questionnaire alone could not ensure that all occu-
pational exposure practices were adequately asses-
sed. In addition, the questionnaire might elicit subjec-
tive information which, while helpful, could lead to
misinterpretation of the actual impact, particularly
where there were few responses from a particular
industry or practice. Therefore,
a
working committee
was assembled composed of individuals with experi-
ence and knowledge in radiation protection from a
wide variety of industries and practices. The member-
ship included: from medical activities (Larry
Brennecke and Thomas McLeod); from industrial
NUREG/CR-6112
8
radiography (Thomas M. Gaines); from well logging
(George O'Bannion); from the university community
(Howard K. Elson); from nuclear power plants (Frank
Rescek); from nuclear plant contractors (Frank
Roddy); from fuel fabricators (Robert Robinson); from
NUMARC (Ralph Andersen and Jay Maisler); from the
Nuclear Regulatory Commission (George Powers and
Alan Roecklein); and from the Department of Energy
(Anthony Weadock). Bruce Dionne and Tasneem
Khan of the BNL AURA Center also participated.
The working committee met on March 27,1991 to
review the data from the questionnaires. They also
reviewed the study by the DOE on the implications
of
BElR V to the DOE, and the BNL ALARA Center
study on highdose worker groups at nuclear plants
(both are discussed elsewhere in this report). Addi-
tional data was received from the participants during
the meeting, and areas requiring more information
were identified.
After this meeting, questionnaires were mailed to
additional radiographers, fuel-fabrication workers, and
nuclear-plant contractors.
A
letter in the October 1991 ssue of the Health Phys-
ics Society Newsletter summarized the information
from the responses received up to that point. This
letter specifically requested comments and sugges-
tions. Because there were no responses, a follow-up
letter was published in the March 1992 ssue. Only
two responses were received by the endof May.
A second meeting of the working group was held in
July 1992 when several specific comments and sug-
gestions were made (see Chapter
5).
3.3 Comments Received
to
the
Draft NUREG Report
The NUREG/CR-6112 Draft Report was distributed for
public comment in early 1994. Seven sets of com-
ments were received. This additional information
included comments and data from the nuclear power
plant community, the fuel fabrication community, the
radio-pharmaceutical production community, and the
industrial radiography community. The comments
have been addressed in Section4.5, and much of the
data and detailed comments are included in Section
5.
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4.1
4 Survey Results
Edison E lectric Institute (EEI)
Report
I
m
4.1
I
Administrative Control Levels
In the EEI Report
(EEI, 1991)
twenty-seven people
reported administrative control levels:six use a
5
rem
annual limit ; eight have adopted a
4.5
to
4.9
rem yr'
value; eleven use an annual control level of approxi-
mately
4
rem yr ' (which was the guideline published
by the Institute of Nuclear Power Operations (INPO)
in
1988);
and
two
have adopted progressive levels of
2.5 rem yr'.
4.1.2 Annual Reported Doses for 1985
and 1989
Figure
4.1
(taken from the
EEI
Report) shows the
number of workers from
11
sites
with
annual doses
greater than
0.5,l
.O,
2.0,3.0,4.0,
and 5.0 rem in
1985
and
1989.
The data include both u t i l iperson-
nel
(UT)
and total personnel
(TO)
which includes
contractors. Figure
4.2
(also from the same report)
shows the percentage of u t i l i personnel and total
personnel
with
annual doses greater than these dose
values for the same two years. The contractor. doses
are only those reported by the individual utilities and
may not reflect their total dose @e. he sumof doses
received at two or more sites).
Figure
4.1
Annual Side
Doses
fo r Utility Personnel
(UT) and Total Plant Workers
(TO) (11
Responders)
9
Figure 4.2 Annual Site Doses for Utility Personne
(UT) and Total Plant Workers (TO) fo r
1985
and
1989
There is a clear decrease in the number and percent
age of both utility and total personnel above each
dose value in
1989
relative to
1985.
No person ex-
ceeded
5
rem yr'.
About 8% (967)
of the people at
11sites had annual doses greater than2 em yf ' in
1989.
4.1.3 Cumulative Dose Administrative
Guidelines
The survey showed that 13 of the
26
responders had
established some form of a cumulative dose guide-
line, the most common being age times
1
rem. Four
have a review or reference level based on age, or a
cumulative lifetime value, for which individual doses
would be tracked and interventionwould occur. Ten
responders had not established a cumulative guide-
line in
1989
but modwere in the process of adopting
one. We noted that seven responders had adopted a
cumulativedose exemption procedure to exceed,
which typically required the approval of a Vice Presi-
dent, Director,
or
Plant Manager. The report stated
that ...it
is
likely that
in
a few years most nuclear
utilitieswill have in place some form of lifetime or
cumulative dose guidance . In
its
December1991
guidelines, INPO urged utilities to strive to meet the
NCRP recommendation of a lifetime dose not to ex-
ceed the workers age
in
rem.
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Sunrey Results
4.1.4 Cumulative Reported Doses for
1989
Figure4.3 (reproduced from the EEI Report) shows
the number of personnel, from
19
responder
sites
in
1989,with
cumulative doses in the categories
25-50,
50-75,75-100,100-150,nd
>
150 rem for utility and
contractor personnel. TheEEIReport does not show
how many individuals exceed a lifetime dose of their
age in rem, but rather, the number of workers younger
and older than50 that appeared in each cumulative
dose interval.
100
n so
6 - 7 s
s . 1 ~ im-m
Daecawm(rrm)
Figure
4.3
Cumulative Site Doses for Utility and
Contractor Personnel for
1989
(19Responders)
Of this total worker population, less than
50 utility
and
contractor personnel younger than50 had lifetime
exposures greater than50 rem. Other findings on
cumulative doses were:
1)
no
utility
worker had life-
time doses greate-r han
75
rem, and
2)
several con-
tractor personnel had lifetime doses greater than75
rem, and a couple had more than150 em in 1989.
4.1.5
Figure
4.4
(reproduced from the EEIReport)shows
the projected number of personnel from
14
responder
sites anticipated to have cumulative doses in the
same dose categories listed in Section4.1.4.These
numbers are for both utility and contractor personnel
projected from past data trends
out
to
1994.
Projected Cumulative Doses fo r1994
Figure
4.4
Projected Cumulative Site Doses fo r
1994
Utility and Contractor Personnel
(14Responders)
If
these projections are realistic, less than
17
workers
younger than
50
would have cumulative doses greater
than
50
rem
in 1994.
Also, no utility or contractor
personnel are expected to have a lifetime dose
greater than100 rem. The authors of theEEI report
extrapolated this data to the entire nuclear industry If
we assume that the
15
esponders represent one-
fourth of the industry, we might expect about600
workers
with
lifetime doses over
50
rem in
1994,with
about one-fourth of them (e 150, robably all con-
tractors) over
75
rem and one-tenth of them (e
60
contractors) over
100
rem.
4.1.6
Effects of Changing the Annual
Dose Guidance
The
EEI
questionnaire asked:
If
all utilities adopted
Uniform Site Annual Whole Body Dose Equivalent
Administrative Limits (or guidance values), set at the
following values, what difficulties, additional costs, col-
lective dose increases, and AIARA effects do you see
occurring: 4 em, 3 em, 2.5 rem, 2 em, 1 rem,
0.5
rem? The responses o this question were varied,
and complicated by the fact that a similar question
was asked:
If
NRC lowered the
10
CFR
20
annual
committed effective dose equivalent limit to the follow-
ing values, what do you see occurring:
4,3,2.5,2,1,
0.5
rem? The following conclusions were drawn from
the responses:
NUREG/CR4112
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Survey Results
1.
2.
3.
4.
None of the seventeen responders felt that an
annual dose limit of4 rem would affect operations
significantly. (Ten felt the effect would be minimal;
seven said very minor.)
According to seven responders, an annual limit of
3
rem isachievable, but the contractor's workforce
would have to be expanded.
At
2
rem yf',
two
of five responders felt the limit
was achievable. One responder felt the limit was
possibly achievable, and
two
felt
it
would signifi-
cantly affect operations. An example given was
the lack of a qualified labor pool to work outages.
At 1 rem yr', all responders felt operations would
be ...extremely difficult, if not impossible.
4.1.7
Effects of Establishing
a
Cumula-
tive Dose Limit
The questionnaire asked,
If
a cumulative or lifetime
effective whole body dose limit were imposed by the
NRC, what difficulties, additional costs, collective
dose increases, and ALARA effects...do you see
occurring at 3 x'age,2 x age, 1.5 x age, 1x age and
0.5 x age? Because many of the21 responders
already had adopted a 1
x
age administrative guide-
line and had experience with its effects, the responses
were more consistent than those on other questions
about anticipated effects:
1.
2.
3.
Most responders felt that minimal mpact would
occur for ut i l ipersonnelwith a cumulative limit of
3
x age, 2 x age, and 1.5x age; at a level of
0.5
x
age, most saw substantial effects.
The majority of responders felt that minimal im-
pact would occur for contractor personnel at
3
x
age, and about half felt that there would be mini-
mal impact at2 x age.
At a cumulative limit of
1
x age, 11 responders
saw minimal impact on the numbers ofu t i l i
personnel; the 10 other responders mentioned
impacts, such as scheduling problems, lack of
critical plant specialists, increased personnel and
associated dose for certain
jobs,
and additional
costs, e.g., source term reduction modifications/
operations, radiation protection, and salaries.
11
4.
At a cumulative limit of 1x age, only 1 responder
predicted l i l e effect on contractor personnel;20
responders felt there would be impacts. The
same impacts as those listed in
3.
would occur,
but to a greater degree.
5.
At the level of age times
0.5,
most responders
expected substantial effects on utility personnel
and all but
two
see substantial effects for contrac-
tor personnel.
4.2 Department of Energy (DOE)
Report
4.2.1
Cost
Impact
Based on responses from
37
DOE
contractors
(-
60%),
the projected costs for all sites combined for
a 20 mSv (2 rem) annual limit withouta doubling of
the neutron quality factor, and with a doubling of the
neutron quality factor are as follows:
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Survey Results
Personnel
Costs
Modification
Costs:
Initial
Annual
Initial
Annual
Radiation Protection Costs:
Increased Collective Dose
Neutron Qu ali i Factor of 10
Neutron Qualitv Factorof 20
$11M $15M
$279M
$ 3M
$369M
$
4M
$13M
$
5M
103
person-rem
$17M
$ 7M
243 person-rem
As noted in Section 3.1.2, the estimates do not in-
clude the RockyFlats plants and LosAlamos National
Laboratory, which have significant neutron exposures
and collective doses. In addition, the costs associ-
ated
with
more restrictive Annual Limits on Intakes
(ALI) for intakes of radioactive materials and the use
of committed effective dose equivalent are not fully
represented.
4.2.2 Annual Reported Doses, 1978 to
1988
Figure 4.5 (reproduced from the DOE report) shows a
downward trend in the average annual dose equiva-
lent for DOE personnel
with
measurable exposures
from 1985 to 1988.
200
160
100
60
a
Figure
4.5
60
e r e 2
8s 04 85 m
m w 8 a
Yew
Average Annual Dose Equivalent
for
DOE
Workers with Measurable
Exposure, 1978-1988
NUREG/CR-6112 12
The average dose per worker, with measurable expo-
sure, was typically less than 2mSv yrl (200 mrem
yf'),
which is well below both the DOE annual limit of
50
mSv
yf '
(5
rem yf') and the proposed 20mSv
y f '
(2 rem
yf').
The recent decreases are attributable to
DOES continuingALARA efforts and changes inits
mission.
Figure 4.6 (taken from the DOE Report) shows the
total number of DOE employees and
visitors
exceed-
ing 2.0,l .O, and 0.5 rem annually from 1978 to 1988.
Number
of Individdo
( I
1000)
s
'
.
-/iJz \
t \ I
2 -
l.0 n m
1 -
2 0 mm
-
0
1978 79 80
81
82
83
84 85 88 87 lS
Year
Figure4.6 Number
of
DOE Employees and annual
dose 1978-1 988
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Survey Results
In 1988, the total number of
DOE
personnel and visi-
tors exceeding
-
2.0,l
.O,
and
0.5
rem was 35,548,
and 1,862, respectively. If the decreasing trend in
annual doses continues, a very small percentage
(5rem
0
>2rem 331 >1 rem 3,101
Number of Employees with Lifetime Dose Greater Than Age in Rem: 178
Number of Employees with Measurable Dose: 24.098
Annual Collective Dose: 10.915
Table 5.5
1993
Exposure Experience (estimated)
Number of Employees with Annual Doses:
>5rem 0 >2rem 1000 >1 rem
Number of Employees with Lifetime Dose Greater Than Age in Rem: 500
Number of Employees with Measurable Dose:
Annual Collective Dose:
Nuclear Power Reactor Comments
1.
Two rem yrl is a challenge but achievable with
management support.
1
rem yrl
will
require major
modifications and increase in personnel (espe-
cially for older facilities >15 years).
2. LWRswill not be ableto operate with a 1 remyri
limit.
3. Facility modificationsshould not be necessary;
specialized tasks or maintenance evolutions may
result in higher doses for a few individuals &e.,
10-1
5),
more frequent TLD processing may be re-
quired, outage contractors may be unavailable for
work due to dose restrictions.
4. A limit of cumulative age, 3 rem yrl not to ex-
ceed 10 rem in
5
years is workable. We need
flexibility.
5. We are attempting to limitHP Techs to
~1
rem for
1990: it could have been done in 1989. A few
(contractor) employees have> rem than years
may be put out of work. Initial approach to
< 1
rem yri will probably be to hire more people.
6. Costs are extremely difficult to assess.
7. The nuclear power facilities have not provided an
informed, representative response to the question-
naire.
8. We recognize that the current regulatory limits do
not provide a total lifetime dose limitation other
than the defacto limit of5 rem yr' and, therefore,
theoretically allows significant lifetime dose. If the
regulatory limits need updating, the annual dose
limits should not be changed, and a lifetime dose
limit should be instituted equivalent to the NCRP
recommendation of age
=
rem, with the proviso
that persons who have already exceeded this limit
be provided a special annual limit of1-2 rem.
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Questionnaire Results
9. The use of administrative dose limits established
below regulatory dose limits should be considered.
10. Two rem yr ' limit would be difficult and costly, but
achievable for utility workers. However, for con-
tract personnel
it
would be very difficult and ex-
ceedingly costly.
11.
For those individuals who would exceed the life-
time limit of age in rem, a 2 rem yf ' limit would be
necessary n orderto maintain their employment
within the industry.
12. The number of the more highly exposed contrac-
tor staff working our outages ranges from 50-1
00,
each receiving1-2 rem per outage. Since the
contractor staff works up
to
four to five outages
per year, each of the more highly exposed work-
ers becomes restricted by year's end under the
current administrative dose limits of approximately
4
rem yf'. [Note that most of the contractor staff
do not have a high lifetime dose (e.g., 0.2-0.5 x
age in rem), as their employment has not always
been in the higher dose work activities.
13. If lower regulatory dose limits were instituted, the
contractor companies would be forcedto hire
more temporary staff, perform more training,
charge higher rates, and, as a result, increase the
financial cost. More importantly, this would result
in increased collective dose due to using a larger
and less skilled workforce. Likewise, we would
incur an increase in our company Health Physics
and support stars dose since we would be su p
porting a larger, less skilled radiation worker force.
In addition, the use of more temporary, less
skilled workers also increased he probability of
personnel error, which
is
a decrease in nuclear
safety for both the co-workers and the general
public.
14. In the process of setting new regulatory dose lim-
its,
it
is important o understand the dose limitation
system typically in use at nuclear facilities restricts
actual doses to approximately
80
percent of the
regulatory imits; i.e., administrative imits are set
by the utilities well below the regulatory limits.
The use of administrative dose limits provides a
safety margin designed to help the worker avoid
exceeding regulatory limits. Ifthe NRC regulatory
limit were 2 rem yr', nuclear facilities would
essentially be required to set administrative imits
in the rangeof 1.5 rem yr'.
15. In addition to regulatory and administrative dose
limits, the nuclear industry has achieved
successes in steadily reducing individual, collec-
tive, and lifetime accumulated dose to
As
LowAs
Reasonably Achievable(AURA). In light of the
entire system of dose limitation and
A U R A
prac-
tices, we believe current annual dose limits under
the revised 10 CFR 20 provide appropriate and
adequate worker protection. In addition, an
A U R A
costhenefit analysis has not been per-
formed, which indicates that reductions in the
individual's annual dose ustify the expected in-
crease in collective dose.
16. If reduced dose limits must be instituted, we be-
lieve that the important parameter to control
should be lifetime dose, not annual dose. A modi-
fied lifetime limit similar to the National Council on
Radiation Protection and Measurements (NCRPs)
recommendation would be appropriate. The mod-
ification would beto allow a 1-2 rem yrl provision
for persons who are approaching or have already
exceeded this limit. We believe that the Interna-
tional Commission on Radiological Protection
(ICRP) recommendation of 10 rem in five years,
with a yearly limit of
5
rem, would unnecessarily
restrict our operational flexibility.
17.
It
is noted that the dose risk models of BElR
V
do
not make a distinction between the risk for chronic
exposures based on annual dose rates which vary
from 2-5 rem yr', i.e., risk associated with chronic
exposure is primarily a function of total dose.
Therefore, risk associated
with
current regulatory
dose limits could b